Peter had two brothers, Egidius II, who served as Master of the treasury several times, and Gregory III, who was a relative of the royal Árpád dynasty through his marriage.

[10] With the acquisition of Kolozsvár, Peter Monoszló encircled the landholdings of the bishopric's long-time rival, the Kolozsmonostor Abbey (today Cluj-Mănăștur, Romania), forcing the Benedictine friars for unfavorable estate transfers and exchanges.

[11] When Stephen V fell ill and died on 6 August 1272, it marked the beginning of the era of feudal anarchy, when two rival baronial groups struggled for power during the minority of Ladislaus IV under his mother, Elizabeth's regency.

Peter's brothers, Egidius and Gregory laid siege in late August to the Dowager Queen's palace in Székesfehérvár to "rescue" Ladislaus from the rival baronial group's influence.

[15] Until 1275, Matthew Csák and Nicholas Geregye, rivals to each other, became voivodes several times in acorrdance with their baronial groups' rapid rises and falls in those turbulent years.

[16] Romanian historian Tudor Sălăgean considers this donation was never made and It was merely invented in 1275, by Peter Monoszló and the Csák baronial group as argument to justify the seizure of Kolozsvár by the prelate and their supporters in the name of the minor king.

[17] Both Egidius and Gregory lost all political influence for uncertain reasons after 1275, as they had never hold any dignities after that, despite the fact that their allies, the Csák group was able to return to govern the realm even at the end of the year.

[19] The Transyvanian Chapter asked permission at the same time through their envoys, provost Clement and dean Bartholomew from Ladislaus to receive privilege of tax exemption at the transportation of excavated product from the salt mine in Torda (today Turda, Romania).

According to historian Jenő Szűcs, Peter intended to extend the bishopric's influence over the provostry of Szeben (today Sibiu, Romania), but encountered sharp resistance from the Saxons.

The rebellion spread quickly, the infuriated Saxons stormed into the newly built St. Michael's Cathedral, see of the diocese on 21 February, looted the treasury, desecrated the shrines and massacred there about 2,000 asylum seekers, including canons, archdeacons and other priests.

[24] Ladislaus' faithful prelate, Archbishop-elect Nicholas Kán launched a royal punitive expedition against the Saxons in Szeben region in 1278, in the same time with the defeat of the Geregye dominion.

For instance, Leányvár in Szászfenes (today Florești, Romania) was built between 1282 and 1300 to invigilate the local Saxon communities and the rival Kolozsmonostor Abbey,[19] in addition to protect the possessions of the cathedral chapter.

[26] The papal legate Philip, Bishop of Fermo arrived to Hungary in early 1279 to help Ladislaus to consolidate his authority, but the prelate was shocked at the presence of thousands of pagan Cumans in the realm.

[6] Upon Peter's request in 1282, Ladislaus IV confirmed all donations and privileges made by his late father and grandfather in favor of the Diocese of Transylvania, exempting its possessions from the jurisdiction of the voivode and the ispáns of affected counties.

[28] In 1281, local noble comes Stephen accused Peter's two familiares, Michael Chotow and Fuldur forcibly deported thirty-serf families and seized a huge part in the land of Gyovd, near Tasnád (today Tășnad, Romania) for the diocese.

[19] In the same year, Peter filed a lawsuit against three members of the Dara branch of the Csák kindred, Michael, Ugrin and Barc, also owners of Selénd (today Șilindia, Romania), accusing them with arbitrary takeover of the diocese's land, Barátpüspöki in Bihar County.

[19] On 23 June 1283, Peter signed a contract with the deacon of the Saxon ecclesial community in Medgyes (today Mediaș, Romania) to transmit the diocese's share of the collection of church taxes in the area for annual forty silver denari.

[6] For this role, Ladislaus IV temporarily confiscated the diocese's lands of Kolozsvár and Gyulafehérvár, in addition to surrounding areas and associated privileges, but in September 1289, the king has returned them to Peter, when personally visited the episcopal see.

[34] According to a legal document from 1288, local nobles John and Kemény, sons of Mikola had caused 160 silver denari damage to episcopal estates during an unspecific event earlier.

Since the rule of Andrew II of Hungary, it, alongside Ugocsa and Bereg, belonged to the Diocese of Eger, later confirmed by both Béla IV and Stephen V. In the early 13th century, Máramaros was mostly part of Sásvár ispánate.

[40] Andrew extended privileges at other estates in the diocese, Peter received higher revenues, thus decided to renovate the roof of the St. Michael's Cathedral, when entrusted Saxon professionals and architects in May 1291.

[34] When Roland Borsa besieged and captured the Diocese of Várad's fortress at Fenes (today Finiș in Romania) on 23 May 1294, Andrew III held a general assembly and outlawed him.

[42] According to Tudor Sălăgean, the bishop's active policy of acquiring property and building castles, as well as the fact that the cathedral chapter and the land of Székelys were also headed by relatives, suggesting that he wanted to bring Transylvania under the control of his family.

When Charles I signed an alliance with his cousin Rudolph III of Austria in Pressburg on 24 August 1304, Bishop Peter was among the barons and prelates, who did the same thing in a royal charter.

[40] Historian Sándor Hunyadi emphasizes that broad kinship communities (clans) disintegrated at this time, so it does not follow from Michael Bő's support for Charles that his cousin Peter, who probably remained more neutral during the initial phase of the war of succession, would have done the same.

[48] After the death of Andrew III, Peter was interested in a strong central power, supported and influenced by the Catholic Church, while Ladislaus Kán endeavored to strengthen his authority, sometimes by using or abusing his office of Voivode of Transylvania.

Otherwise in 1306, when the voivode was reluctant to recognize the rule of Charles, whose claim had been supported by the Catholic Church, Pope Clement V ordered Vincent, Archbishop of Kalocsa to excommunicate him and to place Transylvania under ecclesiastic interdict.

[49] As a result, Vincent held out the prospect of the same ecclesiastic disciplinary actions against Peter in case he would not excommunicate Ladislaus Kán who had seized the properties of the prelate of Kalocsa.

[34] Peter Monoszló successfully preserved autonomy for himself in the province: he was able to perform judicial functions without Ladislaus Kán's "guardianship", i.e. acted on church incomes, last wills and inheritance cases, and in matters relating to dowry, wages, wedding gifts, and daughters' quarters.

According to the Saxons, who litigated the Transylvanian Chapter in 1309, Bishop Peter participated in that conspiracy, when Ladislaus Kán captured King Otto of Hungary, rival of Charles I, during his visit in Transylvania in 1307, and had him imprisoned in one of his castles.